Aircraft: COMMERCIAL FIXED WING
Phase of flight: Taxi
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown

I was assigned to work a flight to ZZZ another agent was meeting an inbound flight before the outbound and said he needed help with meeting the inbound flight and he asked me if I could assist him. The inbound aircraft was a 737 and the gate had a movable jetway. To the best of my ability on movable jetway I was trying to assist him; I am more familiar with stationary gates that requires slight movement. I was positioned at the end of the jet bridge and when I opened the door; there was room that the door was not touching anything of the jet bridge. Not realizing how a jetway can move and shift if the alignment is not correct will cause damage. I want to request additional training specifically on the movable jetways. I would like to apologize for the assistants under duress that would have cause an aircraft to be out of service. I was assigned to meet an inbound flight. Since I had not met a plane from a drivable jet bridge since I was initially trained in April 2013; I asked another agent if he could assist me in meeting the flight. I was at the controls of the jet bridge and he stood toward the end of the jet bridge and acted as my guide. The aircraft was a 737 and low to the ground so there was a lot adjustments to be made; vertically and directionally. I had to drive the jet bridge back and forth 3 times to correct my approach to the plane. It took around 7 minutes to finally get the jet bridge up to the door and by then I was worried about the outbound flight; could take a departure delay. Since he was positioned at the end of the jet bridge; he went ahead and opened the door for me. The aircraft door opened fully in the locked position without touching any part of the jet bridge or canopy. We then returned to the podium to work the flight. As we were finishing up the flight; a Supervisor came out of the jet bridge and asked me if I had met the inbound. I answered yes; [and] then he asked me to follow him down the jet bridge because he said the aircraft door was jammed. He then called Maintenance to come up to take a look at the situation. A Maintenance employee came up and attempted to un-jam the door but could not so he called his supervisor. The Maintenance Supervisor took a look at it and instructed his employee to move the aircraft back a few inches to un-jam the door. It was successful. The Maintenance Supervisor then inspected the aircraft door and he deemed it undamaged and safe so he closed the door and said we could dispatch the flight. This was the third time I had been assigned to work gates since my initial training in April 2013. This was my first time assigned to meet a flight on a drivable jet bridge. I was very comfortable during my jet bridge training but after 3 months I felt uncomfortable; hence the reason I asked for assistance. The shift I picked up today was going to be at the Lobby and I did not think I would be pulled to the domestic gates. I do believe if I had been assigned more often to the gates in the past 3 months this would have not happened. Gate agent reports difficulties operating the jet bridge controls which he has not operated since training several months prior. All appears well until departure time when the aircraft door is found to be jammed by the jet bridge. Maintenance is able to free the door without damage.